Which card is bet for FS? I hear nvidia cards are better BUT for FS ATI cards are better.

For FS, ATI only. Nvidia renders clouds in some way that if you have many, it slows the system more than with ATI. Apart from that, X1900XTX is generally faster than its counterpart, I think its 7900GTX?

Both produce good cards. If you want to use the Matrox TripleHead solution, you'll want an nVidia card. As of this writing, ATI drivers do not support 3840 x 1024 resolution.http://www.flightsim.com/cgi/kds?$=main/review/th2go.htm